#include
#include
using namespace std;
float f(float x);
int main()
{
float x;
cin >> x;
cout << (f(x)) << endl;<br>}
float f(float x)
{
float y;
float a = 0.65F;
float b = 1.43F;
if (x <= -1)<br> y = 2 * x + sqrt(b*x + 3);
else if (x < 1)
y = acos(x);
else
y = log(pow((x + a),2));
return y;
}